Improvement in burglar-alarms



M. R. PERKINS.

Burglar Alarms.

Patented July 29,1873.

INVENrEJR.

WITNESSES,

AM PHOTO LIT H 0 GPAFH/C 80. N )f/USBORNEZS PROCESS. Y

To all whom it may concern:

UNITED STATES PATENT GFFIcE.

MICHAEL R. PERKINS, ()F PORTSMOUTH, NEW HAMPSHIRE.

IMPROVEMENT IN BURGLAR-ALARMS.

Specification forming part of Letters Patent No. 141,291, dated July 29, 1873 application filed April 28, 1873.

Be it known that I, M. R. PERKINS, of Portsmouth, in the county of Rockingham and State of New Hampshire, have invented certain new and useful Improvements in Alarms, of which the following is a specification:

The nature of my invention relates to an improvementin alarm-bells to be attached to common door-knobs and it consists in a lever attached to the shank of the knob, which, oper-. atin g on another lever when the knob is turned in either direction, causes an alarm to be sounded, as will be more fully described hereafter.

The accompanying drawing represents my invention.

a represents the shank of a common doorknob, over which is passed the two-pronged lever 0, which turns with the knob in either direction. Pivoted to an iron plate, 0, which is secured to the side of the door, is a lever, g, which extends under the shank of the knob, so that whenever the knob is turned one of the ends of the lever 0 will bear down upon it and raise its opposite end upward. To the short end of the lever g is secured any suitable kind of a spring, which keeps the long end pressed upward against the shank or 1ever 0, and to its extreme end is pivoted a spring-dog, 17, for operating the hammer of the bell. As the end of the lever is tilted upward this dog catches under a shoulder on the hammer l, and raises it up acertain distance, when it slips from under it, letting the spring 0 draw the hammer against the bell n and sound the alarm.

Should it not be desired to have the alarm in action at all times the hammer can be raised up and kept from opera-ting by a pin or other device.

This alarm is intended to be secured to the inside of bed-rooms and other compartments, so that persons cannot enter them or even turn the knob without giving the alarm.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

The combination and arrangement of the collar on the knob shank having inclined arms 0 c, the lever g having outer end bent, as shown, and the dog t pivoted atits other end, and bell-hammer l, substantially as shown.

In testimony thatI claim the foregoing as my invention I hereunto affix my signature this 22d day of April, 1873.

MlOHAEL R. PERKINS.

Witnesses:

JAMES D. BUTLER, F. A. BOYLSTON. 

